This invention relates to chemical vapor deposition methods, including atomic layer deposition, and to valve assemblies for use with a reactive precursor in semiconductor processing.
Semiconductor processing in the fabrication of integrated circuitry typically includes the deposition of layers on semiconductor substrates. Exemplary processes include physical vapor deposition (PVD) and chemical vapor deposition (CVD). In the context of this document, xe2x80x9cCVDxe2x80x9d includes any process, whether existing or yet-to-be developed, where one or more vaporized chemicals is fed as a deposition precursor for reaction and adherence to a substrate surface. By way of example only, one such CVD process includes atomic layer deposition (ALD). With typical ALD, successive mono-atomic layers are adsorbed to a substrate and/or reacted with the outer layer on the substrate, typically by successive feeding of different precursors to the substrate surface.
Chemical vapor depositions can be conducted within chambers or reactors which retain a single substrate upon a wafer holder or susceptor. One or more precursor gasses are typically provided to a shower head within the chamber which is intended to uniformly provide the reactant gasses substantially homogeneously over the outer surface of the substrate. The precursors react or otherwise manifest in a deposition of a suitable layer atop the substrate. Plasma enhancement may or may not be utilized, and either directly within the chamber or remotely therefrom.
In certain chemical vapor deposition processes, including ALD, precursors are pulsed or otherwise intermittently injected into the reactor for reaction and/or deposition onto a substrate. In many cases, it is highly desirable to turn the individual precursor flows on and off very quickly. For example, some deposition processes utilize plasma generation of a precursor in a chamber remote from the deposition chamber. As the precursor leaves the remote plasma generation chamber, such typically converts to a short lived, non-plasma desired active state intended to be maintained for reaction in the deposition chamber. Yet plasma generation in the remote chamber is very pressure dependent, and the plasma typically ceases in the remote chamber when switching/pulsing the active species flow to the chamber. Accordingly, such process are expected to utilize pulsed remote plasma generation, and which may not be practical.
The invention was motivated in overcoming the above-described drawbacks, although it is in no way so limited. The invention is only limited by the accompanying claims as literally worded without interpretative or other limiting reference to the specification or drawings, and in accordance with the doctrine of equivalents.
The invention includes chemical vapor deposition methods, including atomic layer deposition, and valve assemblies for use with a reactive precursor in semiconductor processing. In one implementation, a chemical vapor deposition method includes positioning a semiconductor substrate within a chemical vapor deposition chamber. A first deposition precursor is fed to a remote plasma generation chamber positioned upstream of the deposition chamber, and a plasma is generated therefrom within the remote chamber and effective to form a first active deposition precursor species. The first species is flowed to the deposition chamber. During the flowing, flow of at least some of the first species is diverted from entering the deposition chamber while feeding and maintaining plasma generation of the first deposition precursor within the remote chamber. At some point, diverting is ceased while feeding and maintaining plasma generation of the first deposition precursor within the remote chamber.
In one implementation, a chemical vapor deposition method includes positioning a semiconductor substrate within a chemical vapor deposition chamber. A first deposition precursor is fed to the chamber through at least a portion of a rotatable cylindrical mass of a valve assembly. During the flowing, flow of at least some of the first deposition precursor is diverted from entering the deposition chamber by rotating the cylindrical mass in a first rotational direction. At some point while diverting is occurring, the cylindrical mass is rotated in the first rotational direction effective to cease said diverting.
In one implementation, a valve assembly for a reactive precursor to be used in semiconductor processing includes a valve body having at least one inlet and at least two outlets. The inlet is configured for connection with a reactive precursor source. A first of the outlets is configured for connection with a feed stream to a semiconductor substrate processor chamber. A second of the outlets is configured for diverting precursor flow away from said chamber. The valve body includes a first fluid passageway therein extending between the inlet and the first outlet. The valve body has a second fluid passageway extending between the first fluid passageway and the second outlet. A control plate and/or generally cylindrical mass is mounted for at least limited rotation within the body proximate the first and second passageways. Such includes an arcuate region at least a portion of which is received within the first passageway. The arcuate region includes a first region having an opening extending therethrough and which is positionable into a first selected radial orientation to provide the inlet and the first outlet in fluid communication with one another through the first passageway while restricting flow to the second passageway. The arcuate region includes a second region positionable into the first radial orientation to provide the inlet and second outlet in fluid communication through the first and second passageways while restricting flow to the first outlet.
Other aspects and implementations are contemplated.